Mucoadhesive Drug Delivery Systems

The in vitro interaction of human endothelial cells (HEC) and polymers with different wettabilities in culture medium containing serum was investigated. Optimal adhesion of HEC generally occurred onto moderately wettable polymers. Within a series of cellulose type of polymers the cell adhesion increased with increasing contact angle of the polymer surfaces. Proliferation of HEC occurred when adhesion was followed by progressive flattening of the cells. Our results suggest that moderately wettable polymers exhibit a serum and/or cellular protein adsorption pattern that is favourable for growth of HEC.

An in-vitro test system was developed to investigate the adhesiveness of various materials to mucus. The results obtained showed good agreement with the findings of previous in-vivo evaluations of mucosa-adhesives. Further investigations found that these materials become adhesive on hydration. Chain length, and the presence of ionizable groups in the molecule, were found to be determinate factors. The physical nature of the gel, and the location at which the mucoadhesive materials hydrated, were of less importance.